Answer:
Explanation:
The union of two sets includes all numbers that are within them.
The intersection of two sets only denotes the numbers that are within both sets.
Thus
D U E = [1,∞)
D ∩ E = (9, ∞)
Remember that brackets [ ] are used to indicate numbers that are included within the set and parenthesis ( ) indicate those that aren't.
Because x is greater than or equal to 1, brackets are necessary.